[QUOTE=ewmayer;511252][url=https://www.sciencedaily.com/releases/2019/03/190314151645.htm]Tectonics in the tropics trigger Earth’s ice ages[/url] | Science Daily

So we just need a way to engineer this plate-movement thing...[/QUOTE]Since I don't know much about how weathering of rocks sequesters carbon, I did a bit of searching online. The following looked promising. I especially liked it because it has a number of typos, which alert readers pointed out
:-D

[url=https://www.skepticalscience.com/weathering.html]Weathering and the carbon cycle[/url]

Regarding "engineering" tectonic activity, the results of fracking in Oklahoma might give one pause...

[url=https://www.chicagotribune.com/news/nationworld/midwest/ct-flooding-climate-change-20190322-story.html]Midwest flooding highlights national security risk posed by climate change[/url][quote]The Missouri River floodwater surging on to the air base housing the U.S. military's Strategic Command overwhelmed round-the-clock sandbagging by airmen and others. They had to scramble to save sensitive equipment, munitions and dozens of aircraft.

Days into the flooding, muddy water was still lapping at almost 80 flooded buildings at Nebraska's Offutt Air Force Base, some inundated by up to 7 feet of water. Piles of waterlogged corn cobs, husks and stalks lay heaped everywhere that the water had receded, swept onto the base from surrounding fields.
<snip>
It is also a reminder that the kind of weather extremes escalating with climate change aren't limited to the coasts, said retired Rear Adm. David W. Titley, founder of both the Navy's Task Force on Climate Change and the Center for Solutions to Weather and Climate Risk at Penn State University.

"We probably do need some walls — but they're probably levees," Titley said, in a reference to President Donald Trump's proposal to take money from the military construction budget to fund a wall at the U.S.-Mexico border. "I would say those are the kinds of walls we need."[/quote]Of course, the current flooding has nothing -- nothing at all -- to do with climate change or human activity.

A critical look at the push for renewable energy, via the lens of the multi-decade, hundreds-of-billions-of-Euros-spent German [i]Energiewende[/i] ('Energy Transition') experiment in same:

[url=https://www.nakedcapitalism.com/2019/05/ilargi-renewables-are-dead.html]Ilargi: Renewables Are Dead[/url] | naked capitalism
[quote]The transition to renewables was doomed because modern industrial people, no matter how Romantic they are, do not want to return to pre-modern life. [b]The reason renewables can’t power modern civilization is because they were never meant to[/b]. One interesting question is why anybody ever thought they could.[/quote]

[QUOTE=ewmayer;516174][URL="https://www.nakedcapitalism.com/2019/05/ilargi-renewables-are-dead.html"]Ilargi: Renewables Are Dead[/URL] | naked capitalism[/QUOTE]
Half clickbait half they don't know what they are talking about.. .

[QUOTE=ewmayer;516174]A critical look at the push for renewable energy, via the lens of the multi-decade, hundreds-of-billions-of-Euros-spent German [i]Energiewende[/i] ('Energy Transition') experiment in same:

[url=https://www.nakedcapitalism.com/2019/05/ilargi-renewables-are-dead.html]Ilargi: Renewables Are Dead[/url] | naked capitalism[/QUOTE]

It's [i]much[/i] worse than that!

[url=https://www.snopes.com/fact-check/solar-drain/]Solar Panels Drain the Sun’s Energy, Experts Say[/url]

Oh, wait...

[QUOTE=LaurV;516198]Half clickbait half they don't know what they are talking about.. .[/QUOTE]

Could you be more specific? It's good to debate such things, but driveby "this d00d is clueless" is not exactly a scientific argument.

[QUOTE=ewmayer;516288]Could you be more specific? It's good to debate such things, but driveby "this d00d is clueless" is not exactly a scientific argument.[/QUOTE]

I mean, during the same time Germany floundered around with useless renewable research, France moved its grid almost entirely off coal (though it does still use gas peakers and load followers). It has less to do with what they were 'meant' to do and more to do with German avoidance of nuclear power.

[URL="https://www.theguardian.com/environment/2019/may/08/britain-passes-1-week-without-coal-power-for-first-time-since-1882"]Britain passes one week without coal power for first time since 1882[/URL]

Of course, unlike Germany, UK hasn't started shutting down its nuclear plants and is actually investing in new ones.

[QUOTE=ewmayer;516174]A critical look at the push for renewable energy, via the lens of the multi-decade, hundreds-of-billions-of-Euros-spent German [i]Energiewende[/i] ('Energy Transition') experiment in same:

[url=https://www.nakedcapitalism.com/2019/05/ilargi-renewables-are-dead.html]Ilargi: Renewables Are Dead[/url] | naked capitalism[/QUOTE] Hmm. It cites an article from [i]Der Spiegel[/i].

I have it from [url=https://www.mersenneforum.org/showpost.php?p=503717&postcount=81]an unimpeachable source[/url] that [i]Der Spiegel[/i] is [i]not[/i] an unimpeachable source. This is covered in many other places, e.g. [url=https://www.theatlantic.com/international/archive/2019/01/der-spiegal-fabrication-scandal-global/579889/]here[/url].

Apart from that, the cited post appears to argue that renewable energy is a hopeless quest [i]because[/i] the German program was a fiasco. This argument does not really address the issue of whether "renewable" energy (derived from mining sunlight) is capable of supplying the amount of power required by modern civilization.

I don't see any real physics argument against using a larger fraction of sunlight to supply human needs. IIRC the strength of sunlight is about a kilowatt per square meter (hitting it plumb) at our distance. You can calculate how may square meters you'd need to create x amount of power at such-and-such efficiency.

Certainly wind and solar (photovoltaic) power -- as presently constituted -- are unlikely to supply more than a small fraction of present needs. Hydro power works on a larger scale, but has huge environmental costs. (I lump it with renewables because the water keeps getting lifted above the dam by Mr. Sun.)

I vaguely recall reading about the idea of using solar energy to generate power in [u]Disturbing the Universe[/u] by Freeman Dyson. I don't think it was photovoltaics. But Dyson at least estimated how much area would be needed to make the idea work, and compared it to the amount of the US (or of the lower 48) that was already paved over, which he said was 1%. I think that figure was on the high side, but the actual amount is probably greater than 0.5%.

There is, if memory serves, a fundamental limitation on how much you can get out of wind farms -- you can't just have one row after another of wind turbines. I no longer remember many details, but the key phrase "Betz number" has lodged in my mind.

I don't classify nuclear plants as "renewable," but their "carbon footprint" surely is much less than that of a coal or gas-fired plant.

[QUOTE=Dr Sardonicus;516301]I don't classify nuclear plants as "renewable," [/QUOTE]You may well think that but I couldn't possibly comment.

Actually, I can and will comment. First a statement of general principle: nothing is renewable, the sun included. In the long run everything is dead.

With that out of the way we can concentrate on reality. When the term "renewable" crops up it is generally used in the sense "inexhaustible for the foreseeable future", the next hundred megayears for instance. Examples include solar (and its processed derivatives such as biomass, wind, and hydroelectric), lunar tidal power and geothermal energy.

It turns out that nuclear fission is renewable in this sense. Seawater contains accessible amounts of uranium and thorium which can be extracted fairly easily. [URL="https://newatlas.com/nuclear-uranium-seawater-fibers/55033/"]The technology[/URL] is very new and came to public attention (well, my attention) only a few weeks ago. The key to its "renewability" is that the ocean is in permanent contact with U and Th containing material. Not only is rock continually being brought up from deep in the crust directly into the ocean, more importantly the material carried by rivers end up almost entirely in the oceans. Disturb an equilibrium, by lowering the U and Th concentration, and more of those elements will be leached into the seawater. There is a very large amount of fissile material in the earth's crust...

Fusion power is also "renewable". There is much more deuterium in seawater than either uranium or thorium.

[QUOTE=xilman;516364]
<snip>
When the term "renewable" crops up it is generally used in the sense "inexhaustible for the foreseeable future", the next hundred megayears for instance. Examples include solar (and its processed derivatives such as biomass, wind, and hydroelectric), lunar tidal power and geothermal energy.

It turns out that nuclear fission is renewable in this sense. Seawater contains accessible amounts of uranium and thorium which can be extracted fairly easily. [URL="https://newatlas.com/nuclear-uranium-seawater-fibers/55033/"]The technology[/URL] is very new and came to public attention (well, my attention) only a few weeks ago. The key to its "renewability" is that the ocean is in permanent contact with U and Th containing material.[/quote]
Fine by me. Perhaps the new technology could be applied to the brine coming out of a desalination plant.

Once we're in the "hundreds of megayears" range, the human habitability of the Earth starts coming into question anyway...

Of course, with fission power, the perennial bugbear is, "What do we do with the waste?"

[quote]Fusion power is also "renewable". There is much more deuterium in seawater than either uranium or thorium.[/QUOTE]Unfortunately, "renewable" does not apply to something that does not actually exist. If fusion were ever to become a source of power analogous to fission here on earth, it would transform the whole picture.